1. Field
The invention relates to a medium powered laser which can direct a well defined laser beam over a distance of a few miles. The beam is directed onto a target to create a source of reflected and/or secondary radiation that can be immediately detected by surveillance or weapon systems to locate, identify and, if necessary, destroy the target.
2. Prior Art
The advent of lasers has provided optical detection systems with advantages formerly found only in radar systems. Due to the small wavelengths involved, optical systems also have many advantages not attainable with radar. Optical systems are not easily countered by chaff or other false signal generators. They can ignore camouflage and identify a target by temperature variations alone. Sometimes a target that normally exhibits large temperature variations, like a tank that has been operating or exposed to strong sunlight, can be parked in the shade and left until it blends effectively into the background. An effective means to raise such targets is to illuminate them with a target designator at close range so that they can be spotted by a sophisticated long range system. Since the designator must be transported on foot to most locations it must be compact and light weight.
Low power solid state lasers using ruby rods and the like best meet this weight requirement. As explained in applicant's U.S. Pat. No. 4,725,787 for a "Phase Conjugated Hybrid Slab Laser" issued Feb. 16, 1988, the usual round rod makes a very stable reference source, but any attempt to develop the power required for effective illumination of a target produces undesirable thermal lensing and binefringence and greatly reduces the efficiency of the rod. The patent described a slab laser which is much more efficient. An object of this invention is to employ such a laser in a target designator.